<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        *{
            margin: 0;
            padding: 0;
 }
ul{
    /* 设置最大圆 */
    width:300px;
    height:300px;
    border: 1px solid black;
    border-radius:50%;
    /* 利用弹性使其两个小圆垂直居住 */
    display: flex;
    justify-content: center;
    align-items: center;
    justify-content: space-evenly;
    z-index: 2;
}
/* 设置两个小圆 */
.box,.boxz{
    width:80px;
    height:80px;
    border: 1px solid rgb(20, 19, 19);
    background-color: rgb(250, 243, 243);
    border-radius: 50%;
    z-index:3;
    /* 设置层级 */
}
.boxz{
    background-color: black;
}
/* 设置左下半圆 */
.box1{
    width: 150px;
    height: 75px;
    background-color: rgb(0, 0, 0);
    border-radius: 0 0 150px 150px ;
    position: absolute;
     top: 151px;
     left: 1px;    
}
/* 设置又上半圆 */
.box2{
    width: 150px;
    height: 75px;
    background-color: #fff;
    border-radius:150px 150px 0 0;
    position: absolute;
    z-index: 1;
     top: 76px;
     left: 151px;
}
/* 设置正上方半圆 */
.box3{
    width: 300px;
    height: 150px;
    background-color: black;
    border-radius: 150px 150px 0 0 ;
    position: absolute;
    top: 1px;left: 1px;
}
    </style>
</head>
<body>
    <ul>
        <div class="box"></div>
        <div class="boxz"></div>
    </ul>
    <div class="box1"></div>
    <div class="box2"></div>
    <div class="box3"></div>
</body>
</html>